Priority is claimed to Korean Patent Application No. 2004-7210, filed on Feb. 4, 2004, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a mobile body such as a robot, and more particularly, to a method and apparatus for generating a magnetic field map containing information on a magnetic field affecting a mobile body and a method and apparatus for checking pose of a mobile body using a magnetic field map.
2. Description of the Related Art
A robot needs to accurately recognize its present position to control or monitor its movement. To this end, a map containing information on surrounding environment of the robot is needed.
A topological map method and a grid map method are conventional methods to provide a map. The topological map method is disclosed in a thesis entitled “Topological Mapping for Mobile Robots using a Combination of Sonar and Vision Sensing” written by D. Kortenkamp and T. Weymouth and published in 1994 in Proceedings of the Twelfth National Conference on Artificial Intelligence, at pages 979-984. Also, the grid map method is disclosed in a book entitled “Sensor Fusion in Certainty Grids for Mobile Robots” written by H. P. Moravec and published in 1988 by Al Magazine, vol. 9, no. 2, at pages 61-74.
The conventional topological map method represents the topological relationship among major landmarks in the surrounding environment of a robot as a map. Since the conventional topological map method does not use geometrical information, the conventional grid map method is mainly used to identify an accurate position of a robot.
According to the conventional grid map method, a space in which the robot moves is divided into grids having a certain size and a probability of occupying a grid is generated as a map using a sensor. That is, the conventional grid map method can approximately show the space occupied by a wall and obstacles around the robot using a sensor such as an ultrasonic sensor, an infrared ray scanner, a laser scanner, or a stereo camera. However, since the ultrasonic sensor and the infrared ray scanner have a large amount of noise, the result of sensing may be inaccurate. In addition, although the laser scanner may bring a relatively accurate result, it is expensive and may have a result distorted by a glass material. Moreover, since the stereo camera is sensitive to a change in illumination around the robot, a distorted result may be brought. Further, the stereo camera is not put to practical use because recognizing the landmarks through image processing is very difficult.